// Problem: 
// Contest: 
// URL: 
// Memory Limit: 
// Time Limit: 
// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read(){
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')w=-1;ch=getchar();}
	while(ch>='0'&&ch<='9') s=s*10+ch-'0',ch=getchar();
	return s*w;
}
signed main()
{
	int a,b;
	cin>>a>>b;
	vector<int> v;
	int x,y;
	for(int i=99;i>=0;i-=2)v.push_back(i);
	for(int i=0;i<=98;i+=2)v.push_back(i);
	for(int i=0;i<100;i++)
	{
		if(v[i]==a)x=i;
		if(v[i]==b)y=i;
	}
	cout<<abs(x-y)-1;
	return 0;
}
